Lubricant



Patented Nov. 12, 1946 PATENT OFFICE 231L032 LUBRICANT Ernest F. Engelke and William w. Odell, El Dorado, Aria, assignors to Lion Oil Company, a corporation of Delaware No Drawing. Application January 11, 1944, Serial N0. 517,840

9 Claims. (oi. zsz -sae) This invention relates t"an improved lubricant and additive for a lubricant. In particular the invention has to do with the production of a lubricant, particularly a liquid lubricant, which has improved properties through the employment therein of a particular type of material hereinafter referred to as an additive; it also has to do with the particular additive so employed. The improvement made in the performance of a lubricant by incorporating therein the herein described additive is characterized particularly by the formation of less gummy and varnish-like deposits inside the piston heads, piston skirts, behind the piston rings, and elsewhere in internal combustion engines, when the lubricant, an oil in this case, with said additive is used as the engine lubricant. The invention is not limited to lubricants which are normally liquid at room temperatures of 60 to 70 F.

Some of the objects of this invention are as follows:

To produce lubricating oils with high detergent characteristics for the prevention of the formation of gummy, varnish-like and carbonaceous materials which normally form with ordinary engine oil and deposit upon the piston skirts, piston heads, and behind the piston rings causing them to be stuck, in internal combustion engines such as Diesel engines after limited periods of operation.

To produce additives with high load carrying capacity.

To produce lubricating oil additives or high wear reducing capacity on the rings, cylinder walls, and bearings of internal combustion enzines.

To provide a suitable process by means of which said additives can .be produced.

To provide an additive which imparts oxidation inhibiting power to a lubricant when incorporated therein.

Other objects will become manifest from the disclosures made herein. r

We have discovered that oil-soluble phosphorus containing soaps, mixed with high molecularweight alcohols, be these of aliphatic, mixed aliphatic and aromatic, or of purely aromatic or naphthenic nature, when used in proportions of about 1 to 3 percent in a lubricating oil, have the property of controlling the formation and deposition of varnish or lacquer-like materials upon the walls of the pistons, behind the piston rings, and other delicate parts of internal combustion en- Sines when said oil is used as a lubricant therein. The alcohols may be present inthe mixture as such or partially or wholly converted into phosphoric acid esters. I

We have further discovered that such soaps mixed with high molecular-weight alcohols of the 5 nature described above, tend to suppress to an appreciable extent the oxidation of the oil, thereby preventing the formation, in the oil in use, of acids of a corrosive nature.

We have further discovered that the soaps of certain metals, as for instance silver, tend to deposit an extremely fine layer of metal (plating) on the hottest parts of the engine thereby protecting these against the corrosive attack of organic acids which are in some degree formed inside the motor, especially in motors subjected to severe service.

The starting materials particularly used for the production of the additives forming the subject of this invention are waxes such asbees wax, Chinese wax, carnauba wax, degras, spermaceti, etc. Also liquid waxes such as sperm oil, bottlenose oil and others are suitable. When these waxes are saponified certain high molecular alcohols are formed, such as cetyl, myriscyl, myristyl and ciryl alcohols, and the cholesterols. Thus, for example, cetyl alcohol may be obtained from spermaceti; myriscyl alcohol from carnaubawax; cholesterol from degras or wool-fat; and ciryl and myristyl alcohols from beeswax. Japanwax, be-

30 ing a glyceride, is not considered for usein this invention, nor are the so-called animal and vegetable fats, .which are, with very few exceptions, esters of low molecular weight polyhydric alcohols, mainly of glycerine. I

Also the heavy metal soaps of acids obtained by oxidizing long-chain paraflinic hydrocarbons, as for example parafiine wax, in the liquid phase with air and a suitable catalyst at relatively low temperatures, usually around 160 0., such as for in- 40 stance those of silver and copper, are suitable particularly when employed in conjunction with a high molecular weight monohydroxy hydrocarbon compound. The oxidation of long chain parafflnic hydrocarbons may be conducted so that 45 besides petroleum acids substantial amounts of high molecular monohydric alcohols are formed; thus a mixture is obtained which may be regarded as identical or at least very similar to amixture obtained in the saponification of natural waxes.

The preparation of additives according to this invention comprises the following steps. spermaceti, for example, is saponified in the conventional way with soda lye, yielding a mixture consisting mainly of cetyl alcohol and sodium palmi- 55 tate. By acidifying the reaction mixture, the

ture. The dry product, chiefly cetyl alcohol and palmitic acid, is then subjected to phosphorization by means of heating and stirring same with percent, based on the weight of the charge, of phosphorus pentoxide, or 2 to 2.5 percent 'of elemental yellow phosphorus. The temperature of the reaction mass is gradually raised to about 390 F. and kept there 4 to 6 hours. The mass is then allowed to settle at about 200 F.'whereby a small amount of sludge usually forms regardless of which of the two agents is used to effect the phosphorization. The clarified or partly clarified supematent mixture is then passed through a finemesh strainer for removing any suspended sludge and then digested at water bath temperature, commonly about 200 F'., with the requisite amount of dilute caustic soda lye to bring the palmitic acid into solution. The sodium palmitate is then precipitated with the requisite amount of silver nitrate to convert the sodium palmitate to silver palmitate. The phosphorized mixture of cetyl alcohol and silver palmitate is separated from the mother liquor, thoroughly washed with hot water and dried by heating under agitation at about 280 to 300 F. The product thus obtained is dark colored and it is readily soluble at slightly elevated temperatures in light or heavy motor 0115. At room temperature the product is solid. It melts at about 150 to 160 F.

Example 1 Use of oil with silver-containing additive. This additive, prepared as described above, of which 0.6 percent was added to a SAE 30 oil was tested under high temperature automotive conditions for 'lz-hours in a number of Lauson engines. After these tests the engines were found to be in extremely good condition and there was extremely little engine deposit. The piston rings and ring grooves were in excellent condition and the ring wear was very low. When the same SAE 30 oil without the additive was tested in a similar manner in Lauson engines for 72-hours the engines were not in good condition after the run period, and there were considerable engine deposits; some of the piston rings were sticking because of deposits in the ring grooves. Furthermore, the wear and bearing weight loss were appreciably higher when the straight lubricating oil without additives was used in these engine tests. This additive thus possesses both the prop- :rties'of a detergent and an inhibitor of oxidaion.

A 96-hour test of the same 011 using the same amount of the same additive therein (0.6 percent) under high temperature automotive conditions (namely. 190 F, cooling water outlet temperature and 285 F. temperature of oil in the pan) gave the following favorable results. Only very slight lacquer formation was in evidence on the pistons and engine parts, not the slightest indication of ring sticking appeared, and the holes in the oil ring were not plugged, which indicates the excellent detergent properties of the additive. The ring weight loss was extremely low and the bearing weight loss was also low. After an extended period of engine operation, the outer sides of the piston rings showed, instead of a carbonaceous deposit commonly found with average engine oil, a slight mirror like deposit of silver.

A commercial grade of neutral degras was saponifled in the conventional manner with caustic soda, and the purified and dry saponiflcate was converted by means of P205 in like manner as described in the foregoing example to a phosphorized product, and then converted by means of silver nitrate solution to the silver soap, which was washed and dried in the usual manner. Of this material, including the high molecular weight alcohol formed during saponiflcation, 0.6

percent was incorporated into a SAE 30 grade motor oil and the mixture subjected to a 72-hour test run in Lauson engines under high temperature automotive conditions. The results obtained in this test were the following:

A small amount of lacquer formed on the various parts of the engine but there was not the slightest indication of ring sticking nor of plugging of the oil holes in the rings. which is indicative of a high degree of detergency possessed by the additive under testing. The bearing weight loss was extremely low.

We have found that by similarly using other metals in the place of silver, for example zinc, lube oil additivesof a high degree of effectiveness can be produced in a manner analogous to that according to which the silver soap was prepared.

A wax, for example spermaceti, is saponifled and phosphorized in the same method by means of which the silver soap was obtained. By precipitation of the aqueous sodium soap solution with a water soluble zinc salt, the zinc soap is obtained in mixture with the other phosphorized constituents of the original material. The precipitated mixture is separated from the mother liquor, washed free of salts, and dried by heating to 300 F. The dried zinc soap product is readily soluble in heavy petroleum oils.

An SAE 30 motor oil doped with 0.6 percent of the above zinc soap and subjected to a 96 hour run in a 'Lauson motor under high temperature automotive conditions, viz.=l F. head and 285 F. in the pan with the following results: There was very little lacquer formed on the piston and on the inside of the engine. The piston rings were perfectly clean and free and no trace of plugging of'the oil holes in the rings could be detected. This is a strong indication of good detergency of the zinc additive. The bearing weight loss was very low and neither the piston rings nor the cylinder walls showed any loss due to wear.

The additives described in the foregoing were found to be very useful as extreme pressure oil additives as may be understood from a study of the results given below. i

The phosphorized mixture composed of monoatomic alcohols and heavy metal soaps obtained from the various kinds of waxes when subjected to the treatment described in detail in the foregoing showed very considerable film strength enhancing capacity when tested with a Falex filmstrength testing machine. An SAE 30 grade motor oil of Mid-Continent origin showed when tested with and without the silver additive the following results:

Blank (average of three tests) -failure at a Jaw pressure of 900 Oil plus 1 percent silver additive, also average of three tests-failure at 2400 which represents a gain of 2'10 percent in the load-carrying capacity of the doped oil.

Because lacquer deposits in engines is not always due to straight oxidation of the lubricant but frequently to polymerization as well, and because nitric oxide present in engine products of combustion is a catalyst to the formation of lacquers of this type, we have studied these factors and we have found by experiment that the effectiveness of the above described additives is enhanced with respect to reduction of lacquer formation by using them in combination with such materials as phenols, aminophenols and aromatic tertiary amines or combinations of them.

Before defining our claims, attention is called to the fact that the nature of the small amount of carbon deposited on the piston heads of an engine operated with the use of an engine oil employing the above described additives is radically difierent from that formed when the same oil without the additives is thus employed. The carbon formed, when the above described additives are employed, is soft and can readily be removed from the piston head, whereas when no additive is employed in the lubricating oil the carbon formed is not only much greater in amount but it is hard and adheres to the metal.

In employing aromatic amines we have found it possible to make excellent general purpose mixed additives in which the above described metal soaps are included, for example:

Percent Silver soap as described 0.3' to 3.0 Dialkylated aniline of which dimethyl aniline is representative 0.2 to 0.5 Engine oil sufficient to make 100 percent Percent Silver additive as described herein 0.3 to 1.0 Dimethyl aniline 0.2 to 0.9 Tertiary butyl phenol 0.3 to 2.0

Engine oil suificient to make 100 percent The examples presented herein are for the purpose of illustrating this invention which is not limited in scope to the specific illustrations.

Having described our invention so that one skilled in the art can practice it, we claim:

1. A lubricant suitable for use in an internal combustion engine, comprising a major proportion of an oil having lubricating characteristics and a minor proportion of an additive suificient in quantity to prevent oxidation of the lubricant, the sticking of piston rings and the corrosion of bearings, said additive comprising a phosphorized mixture of a soap and a higher molecular monohydric alcohol, said soap beingderived from a heavy metal and a member of a group consisting of natural waxes and artificial wax mixtures obtained in the catalytic oxidation of high molecular hydrocarbons of parafflnic crudes, the mixture being phosphorized by the use of a member of a group consisting of elemental phosphorus and phosphorous pentoxide.

2. A lubricant suitable for use in an internal combustion engine, comprising a major propor- 6 v tion of an oil having lubricating characteristics and a minor proportion of an additive sumcient in quantity to prevent oxidation oi. the lubricant, the sticking of piston rings and the corrosion of bearings, said additive comprising a phosphorized mixture of a soap and a high molecular monohydric alcohol, said soap being derived from a heavy metal and a member 01' a group consisting of natural waxes and artificial wax mixtures obtained in the catalytic oxidation of high molecular hydrocarbons of parafllnic crudes, the mixture being phosphorized by the use 01 a member or a group consisting of elemental ph sp nd phosphorous pentoxide, the soap included in the additive being a silver soap.

3. A lubricant suitable for use in an internal combustion engine, comprising a major proportion of an oil having lubricating characteristics and a minor proportion of an additive sumcient the sticking of piston rings and the corrosion of bearings, said additive comprising a phosphorized mixture of a soap and a high molecular monohydride alcohol, said soap being derived from a heavy metal and a member of a group consisting of natural waxes and artificial wax mixtures obtained in the catalytic oxidation of high molecular hydrocarbon of parafiinic crudes, the mixture being phosphorized by the use or a member of a group consisting of elemental phosphorus and phosphorous pentoxide, the soap included in the additive being a zinc soap.

'4. A lubricant suitable for use in an internal combustion engine, comprising a major proportion of an oil having lubricating characteristics and a minor proportion of an additive suflicient in quantity to prevent oxidation of the lubricant, the sticking of piston rings and the corrosion of bearings, said additive comprising a phosphorized mixture of a soap and a high molecular monohydric alcohol, said soap being derived from a heavy metal and a member of a group consisting of natural waxes and artificial wax mixtures obtained in the catalytic oxidation of high molecular hydrocarbons of parafilnic crudes, the mixture being phosphorized by the use of a member of a group consisting of elemental phosphorus and phosphorous pentoxide, the additive including a high molecular monohydric alcohol selected from a, group consisting of cetyl, ciryl, myriscyl and myristyl alcohols and the cholesterols.

5. A lubricating oil suitable for internal lubrication of internal combustion engines, having high detergent properties comprising principally a petroleum oil having incorporated therein a predetermined amount of a phosphorized mixture of a heavy-metal soap of a wax, said predetermined amount varying from about 0.2 percent to about 2 percent of the whole, according to the amount of beneficiation required by said petroleum oil, said mixture including besides the wax soap the alcohol formed in saponifying the wax.

6. A lubricant suitable for use in an internal combustion engine, comprising a maior proprotion of an oil having lubricating characteristics and a minor proportion of an additive suflicient in quantity to prevent oxidation of the lubricant, the sticking of piston rings and the corrosion oi bearings, said.additi ve comprising a phosphorized mixture of a soap and a high molecular monohydric alcohol, said soap being derived from a heavy metal and a member of a group consisting of natural waxes and artificial wax mixtures obtained in the catalytic oxidation of high molecular hydrocarbons of paraflinic crudes, the mixture quantity to prevent oxidation of the lubricant,

being phosphorized by the use of a member or a group consisting of elemental phosphorus and phosphorous .pentoxide, the additive including a small quantityof an organic tertiary amine.

'z. A lubricant suitable for use in an internal combustion engine, comprising a major proportion of an oil having lubricating characteristics and a minor proportion of an additive sufllcient in quantity to prevent oxidation 01' the lubricant, the stickingof piston rings and the corrosion of bearings, said additive comprising a phosphorized mixture of a soap and a high molecular monohydric alcohol, said soap being derived from a heavy metal and a member of a group consisting of natural waxes and artificial wax mixtures obtained in the catalytic oxidation of high molecular hydrocarbons of parafllnic crudes, the mixture being phosphorized by the use of a member of a group consisting of elemental phosphorus and phosphorous pentoxide, the additive including a small quantity of a lacquer inhibitor comprising an aromatic tertiary amine.

8. A lubricant suitable for use in an internal combustion engine, comprising a major proportion of an oil having lubricating characteristics and a minor proportion of an additive sufllcient in quantity to prevent oxidation of the lubricant, the sticking of piston rings and the corrosion of bearings, said additive comprising a phosphoriaed mixture of a soap and a high molecular monohydric alcohol, said soap being derived from a heavy metal and a member of a group consistinl oi natural waxes and artificial wax mixtures obtained in the catalytic oxidation of high molecular hydrocarbons of parafllnie crudes, the mixture being phosphorized by the use of a member of a group consisting of elemental phosphorus and phosphorous pentoxide, said additive including a small quantity or a lacquer inhibitor comprisinz a member of a group consisting oi phenols, alkyl phenols, amino phenols and alkyl, aryl and aralkyl substituted sulphides.

9. A lubricating oil adapted for use as a lubricant in internal combustion engines comprising essentially a. hydrocarbon oil having incorporated therein approximately 0.3 to 2.0 percent of a phosphorized, heavy metal soap 0! a wax along with some of the high molecular weight monohydroxy alcohol formed during the saponiflcation of said wax and a small amount of an inhibitor comprising a member of a group consisting of phenols, alkyl phenols, amino phenols and alkyl, aryl and aralkyl substituted sulphides.

ERNEST F. ENGELKE. WIIILIAM W. ODELL. 

